We sent not an apostle except (to teach) in the language of his (own) people, in order to make (things) clear to them. Now God leaves straying those whom He pleases and guides whom He pleases: and He is Exalted in power, full of Wisdom. (14:4)

One day We shall raise from all Peoples a witness against them, from amongst themselves: and We shall bring thee as a witness against these (thy people): and We have sent down to thee the Book explaining all things, a Guide, a Mercy, and Glad Tidings to Muslims. (16:89)